Highly flexible supercapacitors with manganese oxide nanosheet/carbon cloth electrode

We report a simple and cost-effective synthesis of hierarchically porous structure composed of Birnessite-type manganese dioxide (MnO2) nanosheets on flexible carbon cloth (CC) via anodic electrodeposition technique. Petal-shaped MnO2, having sheet thickness of a few nm and typical width of 100 nm, with a strong adhesion on CC is observed. This hierarchically porous MnO2-CC hybrid structure dose exhibit not only excellent capacitance properties, such as up to 425 Fg(-1) in specific capacitance, but also high crack resistance owing to its efficient release of bending stress, as observed by cyclic voltammetry and galvanostatic charge/discharge measurements under different curvature of bending configurations. Furthermore, flexible supercapacitors based on this kind of MnO2 nanosheet/CC electrode showed significantly improved stability in capacitive performance over 3000 cycles under the bending test, which is highly promising for future applications in flexible energy storage device. (C) 2011 Elsevier Ltd. All rights reserved.